Fractionator annular drain apparatus and method

ABSTRACT

A tank system may be conventional and fixed, or mobile, such as a fracking fluid or other tank trailer. A drain port thereof is fitted with an adapter connecting a snorkel system to drain liquids from near the top of the liquid level in the tank. A snorkel head at the extreme distal end of a tube near the longitudinal center of the tank is suspended by a system of buoys. A flow field controller plate resists formation of vortices near the snorkel head, so it can operate as near the surface as possible, withdrawing the highest grade oil efficiently. At its exit, the proximal end of the tube drains oil through an inner conduit of an adapter at a penetration in the wall of the tank. The adapter forms an annulus around the inner conduit draining tank bottoms directly from the tank.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/234,216, filed Aug. 11, 2016; which claims the benefit of U.S.Provisional Patent Application Ser. No. 62/208,945, filed Aug. 24, 2015and U.S. Provisional Patent Application Ser. No. 62/259,856, filed Nov.25, 2015. All of which are hereby incorporated by reference in theirentirety.

BACKGROUND Field of the Invention

This invention relates to petroleum production and, more particularly,to novel systems and methods for separation of oil.

Background Art

Petroleum production will typically produce some quantity of petroleum,also referred to as crude, or crude oil. It will typically also producea certain amount of water, typically constituted as brine containingsalt and various other minerals. Also, natural gas (methane) and othertrace gases will often result. Within these fluids may also arrive froma well head certain quantities of basic sediments, includingprecipitates, sand, rock chips, other solids, and so forth.

Various separation techniques exist for separating out oil from water,from solids, and from gases. However, eventually, some quantity of oilwill result from the various separation processes that are below thespecified purity. It may have various constituents at concentrationsoutside values required for sale at a specified market value. This typeof oil is called sub-spec or off-spec oil. When oil markets quote aprice for the purchase of crude oil, a quality is specified. Thatquality specification will typically specify the total amount orpercentage of basic sediments (e.g., solids) and water (BS&W) permitted.Oil that does not meet that specification is either unsalable, andcertainly unsalable at the market price, or must be disposed of at alower price and in another manner.

Typically, one disposition of off-spec. oil (outside specified content)may be further processing. However, such processing is expensive anddifficult. Moreover, the entire separation processes and handlingprocesses are themselves problematic.

One need is an ability to empty a tank cleanly and completely,especially of content settled out below the species being extracted. Onedesire is selectively draining an individual layer from any separatorcleanly (unmixed) and efficiently. Minimizing the risk of mixingseparated constituents is difficult to achieve.

For example, fluid mechanics dictates that viscosity of a moving fluidentrains surrounding fluid. Withdrawing oil without entraining a nearbylayer of water is a typical challenge. Draining water without entraining“bottoms” or “tank bottoms” is likewise. “Tank bottoms” are thebottommost sludge in a tank, a large fraction thereof being basicsediments of the BS&W. Cleaning and draining tank bottoms clinging tofloors and walls present their own problems, as well.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the invention as embodiedand broadly described herein, a method and apparatus are disclosed inone embodiment of the present invention as including a tank, which maybe constituted as a fixed, vertical tank or a tank trailer installed ata site. The separation tank or tank trailer may be adapted from afracking fluid mixing tank.

In certain embodiments, apparatus and methods in accordance with theinvention include a snorkel that traverses through a port near the tankbottom. Rising up through water that has separated out below oil, itpasses through, and the murky interface layer or “dispersion band”between the lower water layer (brine) and the upper oil region.

In accordance with the invention, it has been found that oil need not beextracted from a separation tank or separator tank by conventionalmethods. Conventional methods include using the drain ports of variousconfigurations that may already be installed in fracking fluid mixingtanks. It has been found that the conventional valving, and flangeconnections at the bottom extrema of tank trailers may be fitted with anew apparatus including a mating flange with a sub-sized line connectedthereto.

The sub-size line has an outer diameter that is less than the innerdiameter of the bottom port in a tank trailer. By connecting a new valveand flange to a lowest flange of a tank trailer, the tank trailer may bepenetrated for connection of a snorkel. The snorkel is connected tofittings, including various adapters, and the like to the sealed,flanged assembly inserted into the exit port at or near the bottom of atank trailer.

One adapter may include a central line (tube) surrounded by an outerline (annulus). The inflow areas are about equal. Thus, the sludge,constituting “bottoms” may still be drained through the annulus, evenwhile the snorkel drain operates. Oil taken from near the top of thetank exits through the tube. “Bottoms” exit from the bottom of the tankthrough the annulus.

In one embodiment, a large (long) hose may connect to an adapter influid communication and fixed relation to an attaching flange. Theadapter forms the penetration inside the inner diameter of the exit portof a tank trailer. To the adapter is secured and sealed a long extensionof hose that extends from the exit port near one end, typically the backend, of a tank trailer. The snorkel line, hose, or tube will typicallybe sized to extend to about the center of the length of the tanktrailer.

The adapter may connect to a flange of a conventional drain having aninside diameter (I.D.) of about 4 inches. A nominal three inch I.D. tubemay form the snorkel line. Alternatively a smaller (e.g., two ortwo-and-a-half inch) line may act as the snorkel, surrounded by anannulus to drain the bottoms.

At the extreme end of that tube or line constituted by the hoseextending from the adapter will be a snorkel head or simply “head.” Thehead represents an inlet port receiving oil from as high a possible orpractical in the tank. In other words, the head contains one or moreopenings that constitute inlets to receive oil. The head must bepositioned within the proper layer, typically the uppermost layer, andpreferably the uppermost extrema of the uppermost layer in a separationtank. Thereat, the snorkel may withdraw the highest quality, meaning thelightest density and highest purity, meaning the oil containing thefewest impurities.

In order to maintain the snorkel head at the proper altitude, levitationor buoyancy is needed. Typically, a snorkel head itself is formed as atubular member connected to the line, hose, or tube ascending from theadapter at the exit port of the tank trailer. This tubular member orhead is typically formed of metal and includes apertures sized andpositioned to retrieve oil from a top side or upper side thereof.

For example, the contents of a separation tank are necessarily a dynamicquantity. At times, the snorkel head may rise to a position near thephysical top of the separation tank. At other times, the topmost levelor oil level in the separation tank is far below any top cover. The topsurface of the oil interfaces with overlying air. An air region alsocontains some quantity of fumes, water vapor, and the like.

At times, that top oil level may drop all the way down to the tankbottoms. It has been found dangerous, damaging, and economicallydisastrous to allow the snorkel head to touch or draw in the tankbottoms. If the snorkel head inlet draws in tank bottoms (bottom sludge)damage to equipment is immediate, expensive, disruptive, and more. Thus,the snorkel head may have a standoff attached to offset the snorkel headfrom the bottom wall or floor of the separation tank, and thereby abovethe top surface of the tank bottoms.

Typically, a snorkel head should only descend to such a level after allwater has been removed. Nevertheless, there may be occasions where oilhas already been removed, and water is being removed by the snorkel. Incertain embodiments, it is conceivable and within contemplation thatmultiple snorkels could retrieve oil through one and water throughanother. However, it has been found that conventional removal of waterseems to serve adequately.

Water may typically be retrieved by draining out through existing portsabove and spaced some distance away from the bottom wall or floor of theseparation tank. Water may be drained from well below the lowest levelof oil, typically defined by the dispersion band therebetween. Frackingfluid mixing tanks are already equipped with various fixed lines orpipes that extend into the tank certain distances from the ends, and mayconduct fluids out.

In fact, it is possible to use such piping to remove oil. However, ithas been found in accordance with the invention that removing the verybest oil from the very highest location possible provides a moreefficient and cost effective extraction method for separating anddrawing out oil that will be within specification. Thus, it has beenfound that taking oil only from the very best oil available provides thebenefit of improving compliance with specifications. It also permits oiltherebelow to continue to dwell in the separation tank, furtherseparating. Longer dwell times are longer separation times for water todrift downward along with basic solids, while the oil continues toseparate upward.

Elevation of the snorkel head has its own problem. That problem isdefined as a vortex, sometimes called a whirlpool. Most people that arefamiliar with a vortex from watching a bathtub drain its contents.Similarly, ponds and reservoirs in which a sub-surface drain or weir isprovided the drain may also cause a vortex or whirlpool.

The flow field of water flowing toward the drain comes from acomparatively large area and volume. The cross sectional areaperpendicular to the flow reduces in size as the fluid arrives closer tothe drain position. Meanwhile, the pressure drop necessary to move thatflow necessarily requires a differential in pressure from the farthestpoint away from the drain to the point of the drain.

A vortex forms if a drain is too close to a surface of the drainingfluid. The natural flow tends to move in a circular pattern, in whichcentripetal force maintains the water at a distance from a central axisabove the drain. A combination of the circular motion of the fluid andthe pressure differential between the surface and the drain may tend toform a vortex. The science of vortices has been studied, and equationsexist for defining vortices.

Ultimately, vortices, if allowed to draw overlying air into a drainpipe, may damage pumps drawing on the drain pipe. Moreover, even priorto damage, a pump will become less efficient if it is drawing air orother vapors along with liquids. Motors may overrun, equipment may bedamaged or over heated, and other problems may result from drawing airinto equipment through a vortex.

Thus, a dilemma exists for the snorkel head in accordance with theinvention. It is desirable to draw oil from as high in the separationtank as possible. A vortex should be avoided. Vortex theory, meanwhile,insists that vortices may be avoided only by submerging the drain outleta distance below the surface defined by vortex theory. That distancecorresponds to a certain amount of “pressure head” defined in fluidengineering parlance. Head is typically expressed in feet, and signifiesa number of feet of depth above or below a surface or other datum.Pressure head can be exchanged for pressure as force per unit areaaccording to certain engineering equations, described in conventionaltextbooks. This technology is all described in conventional textbooks,and the reader is referred thereto for the definitions of terms andequations for controlling the fluid mechanics.

To lift the snorkel head to the top region of the oil layer in aseparation tank, a buoy system has been engineered. The snorkel head isprovided with a connector to which the buoy system is attached. The buoysystem is separated a lateral distance from the snorkel head, whilemaintaining a minimum vertical distance. A synthetic depth is created bya circular plate that operates as a spacer plate holding the individualbuoys away from one another, and at a specified distance away from theinlet or inlets in the head of the snorkel system.

The spacer plate may also be thought of as a flow field controller.Depth provides two factors to avoid vortices. The first is a broaderflow field from which to draw fluid. For example more distance away froma drain necessarily creates a spherical cross section through whichsurrounding fluid will flow toward the drain point. That spherical crosssection, as it grows, necessarily requires less velocity to pass avolumetric flow rate. Therefore, less pressure differential is requiredto drive fluid through that cross section.

Therefore, when one contemplates the required depth to avoid a vortex,part of that depth provides a radius away from the drain dictating aspherical cross sectional area That cross section must be sufficientlylarge that the velocities and required pressure differentials thereacross are reduced to values easily supported by gravitational forcesacting on the fluid. Another benefit or factor that depth provides is acolumn or column height of fluid that basically constitutes head orstatic pressure above the drain.

In an apparatus and method in accordance with the invention, depth is anenemy to high quality of oil. Therefore, drawing oil at a depth far awayfrom the top surface is not an option. The snorkel head needs to beplaced as close to the surface as possible. Surface air is sure to floweasier than oil. Therefore, it would seem impossible to preventvortices.

However, another governing factor in fluid mechanics is viscosity.Viscosity is a property of fluids that relates to their resistance toflow. Thus, if oil is more viscous, it has a higher viscosity, meaning ahigher resistance to flow.

For example, one may think of honey as a highly viscous liquid. Oil is aviscous liquid, but not typically as viscous as honey. This is notalways true, given that some crude is literally thixotropic (solid atstandard temperature and pressure, and deformable only by application ofa certain threshold force). However, when one thinks of gear oil (e.g.,90 weight oil) or the like, it flows comparatively slowly. Especially incontrast to standard 30 weight oil or 5 weight oil used in modernautomotive engines. Thus, if oil is more viscous, it has a higherviscosity, meaning a higher resistance to flow. Viscosity works for andagainst a vortex.

On the one hand, higher viscosity requires more force and energy tomove, and therefore more pressure or head height to move a fluid againstthe drag forces of surrounding fluids or solids. On the other handhigher viscosity tends to result in greater momentum transfer betweenadjacent molecules of the fluid, thereby transferring momentum andincreasing speed or keeping the flow together.

It has been found that creating a flow field controller, solves thevortex problem. The flow field controller doubles as a spacer plate,keeping supporting buoys away from the snorkel head. It prevents thesnorkel head from gaining access to air at the top surface or along thesurfaces of the buoys.

The flow field controller is set at a diameter, or radius, defining adistance from the inlet of the snorkel head at which the surface of theoil can actually get access to the overlying air. Thus, in order to drawair, the snorkel must draw oil from the surface and underneath thespacer plate or flow field controller plate.

The effective depth is increased by the distance along the radius fromthe outer perimeter of the spacer plate to the apertures in the snorkelhead suspended therebelow. This distance gives opportunity forsurrounding oil to respond to the buoyancy difference between air andoil. Oil will force the air toward the surface, and replace it withheavier oil. Thus, the flow field controller controls the flow field byexpanding the effective spherical distance to which flow is restrictedto gain access to the apertures of the snorkel head.

In order to provide freedom of movement of the snorkel head, a connectoris permitted to move quite freely with respect to the spacer plate. Thatis, the snorkel head may turn, incline, suspend, lie parallel, and soforth. However, the snorkel plate does maintain the connector of thesnorkel head right at the center thereof at all times. Meanwhile, theradius or diameter of the spacer plate is calculated with actual depthto provide a synthetic depth or minimum flow path between the surface ofthe oil at the edge of the plate and the inlet to the snorkel.

That minimum flow path provides two features. One is time. Time permitsoil to back flow or fill in and force out air that may be drawn into theflow field. Second, the minimum flow path provides an equalization ofthe distance fluid must travel to arrive at the snorkel. It effectivelymakes or reduces a sphere, otherwise filled with air in its tophemisphere, into a walled off lower hemisphere of liquid only.

This may be thought of another way. Imagine the inlet to the snorkelrepresented as the center of a sphere. At a significant depth, so deepthat vortices cannot form, one may imagine the image of fluidhomogeneous flowing from all directions through the surface of a spheretoward that center point of the sphere, which is the inlet of thesnorkel. There is no reason, other than an obstruction, why fluidsshould not come equally fast from all directions through the surface ofthat sphere. Of course, that sphere of flow-cross-sectional area shrinksin diameter as the flow approaches the center of the sphere.

However, one may think of the liquid surface in vortex theory as theouter limit of that sphere. In fact, one may move the snorkel upward,such that the sphere becomes a hemisphere. With the snorkel at thesurface, the sphere becomes a hemisphere. However, the upper end of thathemisphere constitutes air. The viscosity of air is so slight, its massis so light, and so forth, that the snorkel will draw almost exclusivelyair.

Thus two extrema exist, the one in a super deep position, wherein theflow field has no surface effects, but presents a uniform sphere offlow. The other extremum is the worst case scenario. Therein, the spherehas an upper hemisphere of air and a lower hemisphere of oil. One maysee that a benefit is made by repair to an apparatus and method inaccordance with the invention. The circular plate closes or walls offthe upper half or the upper hemisphere. Thus, air and all surroundingoil is on effectively equal terms.

It requires the same distance of travel, the same viscous drag, and thesame acceleration from the cross sectional area at the maximum radius ordiameter of the sphere to the smallest diameter sphere constitutedaround the inlet. It thereby imposes uniformity on the flow field of oiltraveling to the inlet.

Passages exiting the tank are further improved, in accordance withcertain aspects of the invention. The penetrations through standardtanks, such as fracking tanks, include a drain, typically of a standardsize and sometimes with a standard valve. Any passage carrying anymaterial out of the tank must necessarily pass through some penetrationin the tank.

Removing each material in turn from the tank requires transition frommaterial to material through the same penetration and valve. Time,labor, cleaning, contamination, and the like would occur in a typicalconduit as it transitions from draining oil, to water, to tank bottoms.

In accordance with the invention, multiple passages may runconcentrically through a single penetration. At least one annulus maysurround a conduit interior thereto. An annulus may be divided about itscircumference to provide multiple channels therein, but such complexityis not necessary.

In one embodiment, a first flange secures an initial conduit housing tothe outside of the tank. The opposite end of the conduit housing mayhave another flange. In one embodiment, that flange may seal the annulusin an end plate that permits the central conduit integrated therewith topass through.

In an alternative embodiment, a third flange on a second housing maysecure to the second flange. The second flange, or structures associatedwith it, thereby seals the annulus with a plate or similar structure.Through such plate or other structure projects the central conduit. Thatcentral conduit may pass through the first or initial conduit housingand into the tank. In the tank it is available to connect to the lineservicing the snorkel. Meanwhile, in either of these embodiments, asecond passage transitions from the annulus to a connector that drainsthe tank volume directly through the annulus and into a line alwaysseparate from the connections and lines servicing the central conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will become more fullyapparent from the following description and appended claims, taken inconjunction with the accompanying drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are,therefore, not to be considered limiting of its scope, the inventionwill be described with additional specificity and detail through use ofthe accompanying drawings in which:

FIG. 1 is a perspective of one embodiment of a separation tank adaptedfrom a fracking fluid mixing tank trailer;

FIG. 2 is a perspective view of a partially cut away separation tank,illustrating a snorkel penetration into the tank, and its distal endsystem of buoys and flow field controller plate, as well as a manway bywhich access may be made for installation and servicing of a snorkel inaccordance with the invention;

FIG. 3 is a top plan view of the systems of FIGS. 1 and 2 taken atsection A-A;

FIG. 4 is a side elevation view thereof taken at section B-B;

FIG. 5 is a perspective view of one embodiment of a snorkel inaccordance with the invention;

FIG. 6 is a side elevation view thereof;

FIG. 7 is a perspective view of the details of the flange and adapteralong with the controlling ball valve positioned at the entry point intothe tank trailer or separation tank in accordance with the invention;

FIG. 8 is a left side elevation view thereof;

FIG. 9 is a perspective view of the flange adapter;

FIG. 10 is a front end elevation view thereof;

FIG. 11 is a left side elevation view thereof;

FIG. 12 is a perspective view of one embodiment of a snorkel head withits connector and apertures;

FIG. 13 is an end elevation view thereof;

FIG. 14 is a side elevation view thereof showing the apertures on anupper half thereof;

FIG. 15 is an upper perspective view of one embodiment of a buoy systemin which individual buoys are connected to support a flow fieldcontroller or spacer plate;

FIG. 16 is a lower quarter perspective view thereof, illustrating theattachment of the snorkel head thereto;

FIG. 17 is a top plan view thereof;

FIG. 18 is a side elevation view thereof, with the snorkel headdescending directly and vertically upward, or downward;

FIG. 19 is a side elevation view thereof with the snorkel angled atabout a forty five degree angle from horizontal;

FIG. 20 is a side elevation view thereof illustrating the snorkel in avirtually horizontal orientation;

FIG. 21 is a perspective view of an alternative embodiment of a snorkelhead;

FIG. 22 is a side elevation view thereof;

FIG. 23 is an end elevation view thereof;

FIG. 24 is a chart illustrating a graph of oil viscosity in centipoiseas a function of true crude oil gravity measured in degrees API, thedifferent curves representing different grades and all measurementstaken at a uniform temperature, while the baseline viscosity is that ofwater at twenty degrees centigrade;

FIG. 25 is a chart illustrating an equation, in two forms, metric andEnglish units, with definitions of parameters represented in thoseequations;

FIG. 26 is a perspective view of a snorkel system in accordance with theinvention having an adapter for draining two flows, one through acentral conduit and the other through an annular conduit around thecentral conduit, each arriving at a different valve and drain tube,receiver, or the like;

FIG. 27 a top plan elevation view thereof;

FIG. 28 is a front end elevation view thereof;

FIG. 29 is a right side elevation view thereof;

FIG. 30 is a partially cut away, perspective view of an alternativeembodiment of an adapter providing an inner conduit and an outer,annular conduit for receiving two flows from different locations, onethrough a snorkel from near the top of a tank, and one from the bottomof the same tank;

FIG. 31 is a top plan view thereof;

FIG. 32 is a front end elevation view thereof; and

FIG. 33 is a schematic block diagram of a process for operating aseparation system in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the drawingsherein, could be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of theembodiments of the system and method of the present invention, asrepresented in the drawings, is not intended to limit the scope of theinvention, as claimed, but is merely representative of variousembodiments of the invention. The illustrated embodiments of theinvention will be best understood by reference to the drawings, whereinlike parts are designated by like numerals throughout.

Referring to FIG. 1, in one embodiment of an apparatus and method inaccordance with the invention, a system 10 may provide significantimprovements to separation of comparatively higher quality oil, meaningwithin a specification set by a refinery as a threshold level of qualityfor sale to that refinery. For example, refineries will determine abasic sediments and water (BSW or BS&W) qualification required for saleand purchase of crude oil.

In making that determination, the refinery may be considering thevarious species that will be refined out from crude oil to form variousfuels, solvents, other hydrocarbons, and so forth. Water is considered adegradation and dilution of oil. Refineries most hate water due to theenergy cost of vaporizing it in a fractionating column. A basicsediments are likewise problematic, causing wear, damage, fouling, andso forth, they are not desired. Nevertheless, markets control.Therefore, a price at which a refinery finds that it can purchase crudeoil at a particular quality and in sufficient quantity to meet its needswill effectively determine the market.

Therefore, a system 10 and method in accordance with the invention maybe built to define a vertical direction 11 a, longitudinal direction 11b, and a lateral direction 11 c, orthogonal to both. The directions 11have significance, notwithstanding each is shown as having an axis 11 a,11 b, 11 c extending in opposite directions along a single line. Thevertical direction 11 a corresponds to gravity and gravitational forces.Thus, the direction 11 a is the direction of buoyancy, separation, andsettling. Meanwhile, the longitudinal direction 11 b and the lateraldirection 11 c effectively define a plane that will typically representa horizontal directions when a system 10 is level.

In the illustrated embodiment, a snorkel system 12 is a significantimprovement for a tank 14, such as a tank trailer 14. Typically, a tank14 or tank trailer 14 will include a variety of drains 15 or ports 15 aswell as other fill ports, vents, and so forth. The difficulty withdrains 15 is that they are problematic in management of fluid levelswithin the tank 14. They necessarily require flows of fluids in thelongitudinal direction 11 c across dozens of feet of distance.

Similarly, lateral flows toward one side or another, or toward one end28 a or the other 28 b imply comparatively large distances as comparedto heights in a vertical direction 11 a of any particular layer offluid. Thus, entrainment is always a problem. Entrainment is thatphenomenon of fluid mechanics associated with viscosity of fluids.Viscosity in this context may be thought of as fluid frictionalcharacteristics.

Viscosity is a fluid property and reflects momentum transfer betweenlayers of that fluid in motion. Likewise, viscosity may affect momentumtransfer between two fluids in two separate layers traveling in the sameor different directions. For example, momentum transfer between fluidparticles encourages quiescent fluids adjacent to moving fluids to moveby transferring momentum thereto.

Similarly, fluid drag is associated with viscosity, density, distances,etc. during travel in conduits, or along surfaces. In such conditions, asolid wall need not be moving. Momentum transfer between the wall and amoving fluid brings the fluid to a halt at the surface, but establishesa boundary layer of transition between the solid boundary and a freestream of the fluid flow. Within the boundary layer, the viscositypressure, momentum, and energy of the flow will establish a thickness.That thickness is the boundary layer in which the fluid transitions froma stationary velocity at the solid wall to a maximum bulk or free streamvelocity at some distance away from that wall.

Together, the adapter system 16, line 18, which is a flexible line 18 inone currently contemplated embodiment illustrated, the head 20 that willreceive fluid to be taken out of the tank 14, and the supporting buoysystem 22 constitute the snorkel system 12 of the overall system 10. Ina tank 14 in accordance with the invention, certain drains 15 or ports15 may be provided with an adapter system 16. That adapter system 16secures to the drain 15 or port 15 in order to pass therethrough. Theadapter system 16 then connects to a line 18 inside the tank 14. Theline leads upward to a head 20 near the top liquid surface 31. The head20 is supported by a buoy system 22.

The adapter may have a pipe 40 or fitting 40 inside an annulus. The pipe40 connects to the line, while the annulus is exposed to the open tank,near the floor. Outside the flange 42, the annulus and pipe 40 separateto a “bottoms” line and a “saleable oil output” line. Each is valued andpumped.

In practice, it has been found that a flanged penetration 24 defining adrain 15 or port 15 provides access for the adapter system 16.Meanwhile, a manway 16 constituted by a door of sorts that seals muchlike a pressure vessel. It will withstand (e.g., halt) any leakage offluids therethrough. It provides access for personnel to work inside ofthe tank 14. Typically, manways 26 may be located on the top (roof) orbottom (floor) of a tank 14, or on a side wall near the top or bottomthereof, even in the end bulkhead. Meanwhile, a manway 26 may be locatednear the front end 28 of a tank trailer 14, or near the back endthereof, even in the end bulkhead.

Meanwhile, certain of the ports 15 may provide for introduction ofproduction fluids. Production fluids are materials that result frompetroleum production. They may include vapors, liquids, and variouschemical constitutions. Thus, production fluids often include somequantity of natural gas (methane), crude oil (liquid hydrocarbons),water (typically constituted as a brine containing various salts andother chemicals in trace amounts), and basic sediments or solids such assand, and so forth.

In the illustrated embodiment, the flanged penetration 24 providesaccess for introducing the adapter system 16 into the tank 14. The line18 is typically of about the same size or outer diameter as the innerdiameter of the flanged penetration 24. Nevertheless, the line 18 mayactually be somewhat larger than the adapter system 16, since it may fitover a portion of the adapter system 16. Likewise, the line 18 is quitecomparatively long compared to the size of the adapter system 16,meaning length thereof.

The manway 26 may open to provide access to the interior of the tank 14for installing the line 18. Certainly, the line 18 will be secured tothe adapter system 16 after the adapter 16 is inserted through anappropriate drain 15 or port 15, and preferably secured to the flangedpenetration 24. Typical sealing by “O” rings, gaskets, or other types ofseals may occasion installation of the adapter system 16 through theport 15 and securement to the flanged penetration 24.

It has been found to greatly ease the manufacturing process to rely onthe manway 26 as an opening 26 to introduce the buoy system 22. The buoysystem 22 is necessarily quite large, and certainly much larger thananything that would fit as a solid or in a solid configuration through aport 15 and flanged penetration 24. Thus, the buoy system 22 may beinstalled at a distal end of the line 18 before installation inside thetank 14. Alternatively, the line 18 and buoy system 22 may both beinstalled and interconnected inside the tank 14 after an introductionthrough the manway 26.

Similarly, the head 20 will typically be too large to fit through theport 15 or the flanged penetration 24. Accordingly, the head 20 mayeffectively be installed by passing the head 20 through the manway 26.It may either be installed already in the line 18, at the distal endthereof, or installed on the line 18 after both are introduced into thetank 14 through the manway 26.

In one currently contemplated embodiment, the adapter system 16, line18, and head 20 may be preassembled outside of the tank 14. In otherembodiments, either one or both of the adapter system 16 and head 20 maybe secured to the line 18 after the line 18 is positioned inside thetank 14. One reason for installing the line 18 to the head 20 beforeintroduction into the tank 14 is that the line 18 may simply be slippedonto the adapter system 16, not requiring any relative rotation withrespect thereto.

Nevertheless, if orientation of the head 20 is important, then twistingor rotating of the line 18 is a simple matter prior to being secured tothe adapter system 16. Meanwhile, however, the head 20 may be orientedand secured by inserting the head 20 into the line 18 after the line 18is installed. Nevertheless, manipulating the line 18 to orient the head20, after the line 18 and head 20 are secured to one another does notpresent a large, let alone insurmountable, challenge. Moreover, the line18 may have a diameter that becomes much larger than the fitting 40.Such will require introduction through the manway 26.

Referring to FIGS. 1 through 4, while continuing to refer generally toFIGS. 1 through 33, a tank 14 after introduction of production fluidsmay separate those production fluids into different layers 30, 32, 34.Typically, the top layer 30 is an oil layer 30 represented by a topsurface 31. The oil layer 30 may actually be somewhat stratified fromits top surface 31 down toward the water layer 32. Again, the waterlayer 32 constitutes largely water. However dissolved solids, salts, andthe like, as well as other trace minerals or chemicals, may also existin the water 32.

Meanwhile, the tank “bottoms” 34 represent crud 34 or a combination ofbasic sediments mixed with some quantity of hydrocarbons, water, and soforth. The “tank bottoms” 34 or bottoms 34 represent the dregs 34 of thecontents of the tank 14. The dregs 34 or bottoms 34 are very difficultto move, remove, and transport. In fact, one reason for the buoy system22 and the entire snorkel system 12 is to avoid entraining material fromthe water layer 32 or the bottoms 34 when draining the tank 14.

Conventional methods of draining the tank 14 necessarily rely oncomparatively slower processes with extensive monitoring required, lestlayers 30, 32, 34 mix by entrainment, and thus degrade materialsextracted therefrom.

Port locations are poorly adapted for segregated draining. Entrainmentcauses mixing, necessitating slow draining. Long distances exacerbatethis problem.

In one embodiment, the bottoms 34 are contained by the literal bottom 35or tank floor 35. It is a solid wall 35 at the lower extremity of thetank 14.

Meanwhile, above the oil layer 30 is a vapor region 36 or air region 36.Vapors 36 may include air, volatile organic compounds (VOC), some amountof evaporated moisture, and so forth.

The interface 38 between the oil layer 30 and the water layer 32 mayactually represent a dispersion band 38. That is, typically, as waterseparates out of oil and oil separates out of water, each travels in anopposite direction or a direction opposite the other. Oil travels upwardtoward the oil layer 30 from within the water layer 32. Water travelsdownward through the oil layer 30 toward the water layer 32. Sedimentstravel downward from the oil layer 30 and the water layer 32 to arriveat the bottoms 34.

Thus, the dispersion band 38 or boundary 38 actually does not have thetheoretical infinitely thin dimension. Rather, it represents a region 38wherein oil and water in close proximity are separating from one anotherto travel to their respective oil layer 30 and water layer 32.

Referring to FIGS. 5 through 12, while continuing to refer generally toFIGS. 1 through 25, a system 10 in accordance with the invention mayrely on the snorkel system 12 to secure to the tank 14 through a flangepenetration 24 into which is fitted a fitting 40 or adapter 40. A flange42 may be formed as a part thereof, or as an assembly therewith.

The fitting 40 or adapter 40 operates to fit inside the flangepenetration 24. It needs an outer diameter that is less than the innerdiameter that of the flange penetration 24 constituting the port 15 atthe bottom 35 of the end 28 b of the tank 14. The flange 14 is fitted tothe flange penetration 24 constituting the port 15. It has been foundthat a valve 44 secured to the flange 42 provides for control ofdraining the oil layer 30 from the tank 14 through the snorkel system12. The valve 44 may replace any other valving that would otherwise orpreviously been secured to the flange penetration 24.

However, in certain embodiments, the entire fitting 40 or adapter 40 maybe passed through a ball valve. Nevertheless, it has been foundconvenient to secure the flange 42 to the flange penetration 24, therebysecuring the entire adapter system 16 at the port 15 of the tank 14.

The adapter 40 may have a sufficiently small diameter to fit inside anannulus. The annulus fits inside the penetration 24. Separating into thedistinct paths, the annulus and the fitting 40 drain the “tank bottoms”34 and the snorkel line 18, respectively.

In certain embodiments, it has been found affective and convenient torely on conventional barbed texture 46 or “hose barbs” 46 to be receivedinto the line 18. As illustrated, barbs 46 may be secured inside theline 18 on both the proximal and distal ends by compression bands 48.

A significant feature of the snorkel system 12 is the reduction ofobstructions. By making the valve 44 a ball-type valve 44, virtually noobstruction, such as turns, corners, and so forth will exist between thehead 20 and a location outside the snorkel system 12. The only fluiddrag source, after the head 20 would be the fluid drag against the walls(for instance inside wall or inside surface) of the snorkel system 12.However the line 18 may expand to a large diameter after its connectionto the fitting 40. Alternatively the fitting 40 may be adapted by anexpansion to fit a large hose inside diameter.

Another benefit of having a flexible line 18 is that the entire line 18may flex gradually along its length in order to position the head 20 asnear the top surface 31 of the oil layer 30 as possible. However, asclose as possible may be thought of as representing as close aspractical or reasonable. In reality, it has been found that the head 20is best positioned a predetermined distance away from the top surface 31of the oil layer 30. That distance is controlled by minimum vortexdepth.

Speaking of extrema, it is also not beneficial, indeed damaging toprocesses, equipment, and downstream processing systems, methods, andequipment as well for the head 20 to ever ingest or draw in materialfrom the tank bottoms 34 or bottoms 34. The solid content of the bottoms34 clogs, fouls, damages, breaks, and otherwise affects dramatically anddrastically most equipment.

Accordingly, it has been found important to provide a standoff 49engineered to restrain or limit the proximity within which the head 20can approach the bottom 35 of the tank 14. Accordingly, a standoff 49operates in conjunction with the head 20. It operates and even moreparticularly with the buoy system 22 to maintain position andorientation of the head 20.

For example, in the illustrated embodiment, the standoff 49 need onlyprovide a single dimension of spacing of the head 20 away from the floor35 or bottom 35. One reason for this is the buoy system 22. The buoysystem 22, linked to the head 20, stably maintains the orientation ofthe head 20. Thus, the standoff 49 spaces the head 20 away from thefloor 35 or bottom 35 of the tank 14. In particular, the head 20 shouldnot ingest bottoms 34 at any time.

The buoy system 22 may include a plate 50 engineered to provide aneffective vortex depth for the head 20. For example, the plate 50 maysit below the top surface 31 of the oil layer 30 suspended by links 52connecting it to the individual buoys 54. In the illustratedembodiments, the buoys 54 may ride partially submerged, due to their ownweight, the weight of the plate 50, and the weight of the supported head20, and line 18.

For example, referring to FIGS. 5 and 6 as well as FIGS. 15-20, thelinks 52 suspend the plate 50 some distance below the buoys 54.Meanwhile, the buoys 54 provide a density difference or displacement ofthe liquid in the oil layer 30. Buoyancy lifts or floats the plate 50 orsynthetic depth device 50 and the head 20 suspended therebelow.

The effective location through which the apertures 60 or ports 60 in thehead 20 receive fluid (liquid, oil) may be limited to the open channel64 about which the ring 62 or connector 62 secures the head 20 to theplate 50. The apertures 60 may actually be cut into the head 20 from theopening of the channel 64 at the distal end of the head 20 and snorkelsystem 12.

Nevertheless, experiments with a system 10 in accordance with theinvention have demonstrated that apertures 60 on the upper half of thewalls or sides of the head 20 have proven effective to accomplish twofunctions or features. First, they provide a new direction from whichoil can flow more freely. For example, requiring oil to flow from alocation toward the back end 28 b of the trailer tank 14, requires achange of direction of almost 180 degrees to enter the channel 64. Incontrast, by positioning the aperture 60 on the outer surfaces or sidesof the head 20 provides for direct flow of oil from beside the head 20into the channel 64 through the apertures 60 or ports 60.

A second benefit of the positioning of the apertures 60 is to keep themabove the bottom half or the lower side of the head 20 as the head 20descends within the tank 14. The standoff 49 restrains the head 20against moving too close to the floor 35 of the tank 14. Likewise, thelocation of the apertures 60 on the upper half or the top side of thehead 20 assists in limiting flows thereinto from drawing in from below.This is very important when water layer 32 is gone, leaving only thebottoms 34 below the oil 30.

The barbs 66 on the head 20 insert into the distal end of the line 18,thereby facilitating securement of the head 20 to the line 18. Bands 48draw tightly around the line 18 and underlying barbs 66. The variablediameter or radius of the barbs 66 along their length provides forindentation by the barbs 66 into the line 18, under the compressiveloading of force applied by the bands 49. Thus, just as the line 18secures to the barbs 46 of the adapter 40, the line 18 secures to thebarbs 66 of the head 20. The connection is liquid tight.

Referring to FIGS. 7 through 23, while continuing to refer generally toFIGS. 1 through 33, a liquid level 68 lies above a plate 50 or syntheticdepth device 50. The buoy system 22, corresponds to and rides near theliquid level 31 of the oil layer 30 in the tank 14. The effective depthof the head 20 is a calculated or hypothetical value.

For example, from a fluid mechanics standpoint, the head 20 has aneffective aperture center or an effective center for the apertures 60receiving fluid thereinto. Such an effective center may be calculatedaccording to rules of fluid mechanics in any suitable engineering bookon the topic. This provides an effective center, and therefore ahypothetical centroid from which we may measure depth or effectivedepth.

Meanwhile, the level of the plate 50 or synthetic depth plate 50 is alsolocated at some distance below the liquid level 68 or top 31 of the oillayer 30. The actual depth 69 of the centroid or effective center of thehead 20 or the apertures 60 of the head 20 is a physical dimension. Itmay be calculated, measured, and generally known by calculating ahydraulic diameter.

However, in order to protect pumps and other equipment downstream, aswell as the efficiency of flow and pumping, it is best that no airwhatsoever be drawn into the head 20 from the vapor space 36 above theoil layer 30. To that end, it is important to provide a sufficient deptheffective below the surface 68. There the apertures 60 will be located.More will be discussed on this topic hereinafter.

Meanwhile, suffice it to say at this point that the radius 70 of theplate 50 or synthetic depth device 50 is determined according to aneffective distance, and a traveling equivalent to a required depth. Inother words, depth has several influences on a fluid including staticpressure or pressure head caused by submersion to a depth. Likewise, thefluid drag within a continuous body of fluid is another factor.

Meanwhile, the change in cross sectional area available for flow from alarge surrounding region into an aperture 60 is a necessary reduction incross sectional flow area. This has associated with it an increase invelocity as fluid approaches the apertures 60. Meanwhile, turns,obstructions, and the like add hydrodynamic drag. Drag influencespressure differentials between various locations and an aperture 60 ormultiple apertures 60. Flow must travel a certain distance from the freebulk of the fluid in the oil layer 30 to such apertures 60.

Thus, the position of the plate 50 below the liquid level 68, thedistance 69 of the effective centroid of the apertures 60 below thesurface 31, 68 of the oil layer 30, and the radius 70 of the plate 50all contribute to the effective depth engineered for fluid flow of air36. That is to entrain air 36 or vapors from the air region 36 of thetank 14, that air must be drawn into a vortex. A vortex is caused by toorapid a flow at too shallow a depth into the apertures 60.

Herein, a synthetic depth is developed that effectively provides theproper flow field of oil 30 toward the apertures 60, while restrainingair from entering into a vortex by the positioning and sizing of theplate 50.

Referring to FIGS. 24 and 25, while continuing to refer generally toFIGS. 1 through 25, a chart 72 defines axes 74, 76. The abscissa 74 orhorizontal axis 74 represents a property defined or styled as degreesAPI 74. Degrees API 74 will identify a measurement of certain propertiesrelated to viscosity of oil. In reality, degrees API 74 is inversed tospecific gravity or density.

The effective viscosity in centipoise is measured along the ordinate 76.The viscosity in centipoise is represented on a logarithmic scale 76 oraxis 76, while the degrees API is measured on a linear axis 74.

The different curves refer to different constitutions of oil identifiedby a K factor. Measurements in the chart 72 are taken at a temperatureof 100 degrees Fahrenheit. One will see as the degrees API 74 or thevalue increases of degrees API 74, the viscosity 76 in centipoisedecreases. One will also note that the rate of decrease drops off withincreasing value of degrees API 74.

Thus, one will notice that a value of about 1.1 in the dead oilviscosity corresponds to a value of viscosity above that of water. Thevalue of water has a value of one or unity on the vertical axis 76. Mostoil of interest in operating a system 10 in accordance with theinvention has a degree API value of from about 30 to about 42. The chart72 demonstrates that values for water will be suitable for approximationof a conservative vortex depth for oil. In other words, because theviscosity of oil is above that of water in the ranges of interest,calculating a vortex depth using the parameters for water, which has alower viscosity than that of oil, will result in a conservative valuefor effective vortex depth in oil.

Referring to FIG. 25, while continuing to refer generally to FIGS. 1through 33, certain equations are published by the American NationalStandard Institute for hydraulic systems. Standard ANSI/HI 9.8-1998provides the equation 80 a. This equation states that the minimumsubmergence “s” is equal distance to a diameter, (effective length) ofan aperture receiving liquid from a bulk supply thereof. Plus anexpression that is proportional to the flow rate in units of volume persecond divided by a power 1.5 of the diameter.

In such an equation, the velocity is equal to the flow rate “Q” dividedby the cross sectional area determined from the diameter “d.” Thevolumetric flow rate divided by the cross sectional area is the velocity“V.” In the equation 80 a, the units are meters for distance, squaremeters for area, cubic meters for volume, and so forth. Meanwhile, thetime dimension is measured in seconds.

Equation 80 b provides another form of equation 80 a. It uses Englishunits including inches for distance, gallons per minute for volumetricflow rates, and so forth. Thus, area “A” is measured in square inches,whereas a perimeter or wetted perimeter “P” is measured in inches.

Incidentally, or perhaps importantly, diameter is effective diameter orhydraulic diameter. Hydraulic diameter is an important parameter forirregular shapes. In engineering fluid mechanics, a hydraulic diameteris the effective diameter. Hydraulic diameter is defined as four timesthe cross sectional area of a flow region divided by the wettedperimeter of that flow region, or the “circumferential” measurementabout the shape of that cross sectional area. Thus, circular,rectangular, star shaped, irregularly shaped, and other shapes of crosssection may be evaluated and their effective diameters determined.

The diameter 70 of the plate 50 or synthetic depth device 50 isdetermined from a combination of actual depth 69 and the effectivedepth. These depend on depth and distance that flow must traverse toarrive at the centroid or effective opening of the apertures 60.Meanwhile, velocities, areas, and so forth relate to the apertures 60,and are defined thereby. Thus, application of the equation 80 b to asystem 10 in accordance with the invention has provided an effectivediameter 70 of about 15 inches. In practice, this diameter may beincreased, but may only be decreased if flow rates are adjustedaccordingly.

One may see from the equations 80 that the effective depth or thesubmersion “S” is directly proportional to diameter at a first order. Itis also proportional to an inverse 1.5 power of diameter. The submersiondepth is also directly proportional to the volumetric flowrate. However,the addition of multiple terms means that if either the first or secondterm in the equation 80 b becomes disproportionate with respect to theother term, these linear proportionalities may distort and no longer bedirect.

Referring to FIGS. 26 through 29, while continuing to refer generally toFIGS. 1 through 33, an adapter 16 may connect to a line 18 and head 20,as discussed hereinabove, sustained by a buoy system 22. However, at thebottommost region of a snorkel system 12 or general separator system 10in accordance with the invention, the adapter 16 is located to act as adrain system 16 through a penetration in a tank 14 or tank trailer 14.

Accordingly, the flange 42 may connect to a matching portion of a tank14. Here, however, the fitting 40 or adapter 40 operates as a conduit 40conducting fluids from the top of the tank 14. Near the top of theliquid level 68 thereof, by way of the head 20, the attached line 18passes through the layers 30, 32, 34. The conduit 40 or adapter 40defines a passage way passing completely through the adapter 16, toarrive at a valve 14 controlling flow therethrough.

However, in contrast to such an arrangement, standing alone, the adapter16 illustrated here also defines a second passage 100 and second valve84. The first valve 44 effectively defines a first leg 86 a for drainingmaterial from the tank 14. That first leg 86 a is conducting andcontrolling flow exiting the tank 14 through the head 20 and connectedline 18.

In contrast, a second leg 86 b of the adapter 16 connects to an annularregion 100 surrounding the inner conduit 40. For example, the adapter 40adapts the overall adapter system 16 to receive the line 18 over thebarbs 46 or convolutions 46 as described hereinabove. However, theannular region 100 surrounding the conduit 40 is defined by an overallhousing 96 of the adapter 16. The housing 96 may be thought of asdefining the two legs 86 a, 86 b.

Meanwhile, each of the valves 44, 84 has an associated handle 88 a, 88b, respectively or actuator 88 a, 88 b, respectively. In other words, anactuator 88 may be an electrical or mechanical servo controller 88, or amanual handle 88. Herein, trailing reference letters on a referencenumerals indicate specific instances of the item defined by thereference numeral.

Together, the combination of the legs 86 and valves 44, 84 with theirassociated plumbing and controls represent or constitute a fractionator90. The fractionator 90 provides for dividing out various fractions ofthe content of the tank 14. In other words, the fractionator 90 mayconnect by the flange 42 to a wall of a tank 14. Meanwhile, a flange 92may act as a stop for the annular region 100, while allowing passagetherethrough of the inner conduit 40.

In an alternative embodiment, a flange 94 connected to a flange 92 mayactually provide the stop. As a practical matter, something must supportthe inner conduit 40 passing through the flange 92. If the conduit 40 oradapter 40 is welded into the flange 94, then a proper seal between theflanges 92, 94 may act as the seal to seal the annular region 100. Thisis one of the simplest constructions since the conduit 40 simply passesfreely through the annular region 100, and the housing 96. In such anembodiment, the leg 86 b becomes the only exit for the annular region100 or annulus 100.

The conduit 40 defines an internal passage 98. Thus, the lumen 98 may bethought of as a conduit 98, or simply the passage or cavity 98 throughthe inner wall of the adapter 40 or conduit 40. It is not uncommon tospeak of a channel 98 defined by a conduit 40. It is not uncommon alsoto speak interchangeably of the mechanical conduit 40 and the passage 98by the same term. That is, it is well understood that the purpose of theconduit 40 is to create the channel 98. The mechanical device may becalled either.

Similarly, the housing 96 and the conduit 40 define the annulus 100. Itis completely separate and isolated passage 100 directly accessingmaterials near the bottom of the tank 14. Meanwhile, the conduit 40accesses only liquids received through the line 18 and snorkel head 20from near the liquid level 68 or top liquid surface 68 in the tank 14.

Referring to FIGS. 30 through 32, while continuing to refer generally toFIGS. 1 through 33, in certain embodiments, the connectors 102 a, 102 bmay run effectively parallel to one another. For example, in FIGS. 26through 29, the connectors 102 a, 102 b correspond to the legs 86 a, 86b. Accordingly, each of the connections 102 a, 102 b may be thought ofas a conduit 102, tube 102, receptacle 102, or the like. Ultimately,flows through each of the connectors 102 a, 102 b each travel to aseparate container receiving that respective flow through thecorresponding valve 44, 84, respectively.

In the embodiment of FIGS. 30 through 32, the leg 86 b connects tovarious plumbing fixtures in order to redirect the flow contained in theannulus 100 out through the connector 102 b running parallel to theconnector 102 a.

Meanwhile, one can see that the tank bottoms 34 may pass directly fromthe interior of the tank 14 into the annulus 100, and out the leg 86 bcontrolled by the valve 84. Ultimately, whenever the tank bottoms 34 aredesired to be drained, they may be left until the tank 14 is empty ofother contents. The snorkel system 12 effectively drains the desirableoil from the upper reaches of the tank 14, and subsequently any waterlayer 32 thereafter.

Once these over layers 30, 32 have been removed, the tank bottoms 34 maybe dislodged. That may require spraying with high velocity steam, hotwater, or the like as necessary. Sometimes, chemical compositions may beengaged to further dislodge the tank bottoms 34 or sludge 34 from thetank 14.

Once the sludge 34 has been rendered fluid, the valve 44 having beenpreviously closed, the sludge 34 may be drained. Sludge may then passthrough the annulus 100 and out the leg 86 b controlled by the valve 84,once opened. Optionally, a pond, a tank, another truck, or othercontainer may connect to the tank 14 by the connector 102 b. Anintervening line therebetween drains off the sludge 34 or tank bottoms34.

A significant advantage of a fractionator 90 in accordance with theinvention is that the oil lines or the line 18 and its correspondingconduit 40 or adapter 40 need not ever be exposed to tank bottoms 34.Moreover, the valve 44 need not be exposed to tank bottoms 34. Also, thevalves 44, 84 may remain connected at all times, while the cycles offilling, settling, draining, and the like continue. The liquid oil layer30 and the liquid water layer 32 may refill, settle, and drain as oftenas desired. Meanwhile, the tank bottoms 34 may collect, quiesce, settleout, and otherwise accumulate at the floor of the tank 14.

Periodically, the liquids 30, 32 may be drained, typically much morefrequently than the tank bottoms 34. That sludge 34 must be dislodgedand rendered flowable or fluidized to be drained out the annulus 100 andthrough the valve 84 to a waiting receptacle where the receiverconnected to the connector 102. Thus, theoretically, the connector 102is a receiver that receives the flow out of the annulus 100. However, itis contemplated that an initial receiver may be another tank, trailer,or the like for hauling the sludge 34 away for final processing or otherdisposition.

Referring to FIG. 33, while continuing to refer generally to FIGS. 1through 33, a process 110 is illustrated for operating a tank 14 inaccordance with the invention. The process 110 may include introducing112 a mixture of oil, water, basic sediments, and the like. This mixturemay be production fluids or rejected material from previous separationprocesses. As the introduction 112 continues, the liquid level 68 in thetank 14 will rise, causing the snorkel head 20 to rise, lifted by thebuoy system 22.

After filling is complete and waiting 116 for some period of time,stratifying 118 occurs. Thus, the oil layer 30, water layer 32 and thebottoms layer 34 become established.

Periodically, opening 120 the valve 44 effectively opens 120 the line 18to drain. Accordingly, the light species 30 is drained 122. Typically,in a petroleum production scenario, the light layer 30 is an oil layer.Accordingly, draining 122 the light species 30 may be done periodicallywhile allowing the heavy layer 32 to accumulate. Therefore, a test 124determines whether sufficient accumulation of the heavy species 132 hasoccurred.

Efficiency dictates that the accumulated heavy layer 132 should notbecome too large a fraction, as engineered for the tank 14 by theoperating engineer. Accordingly, if the test 124 determines that asufficient quantity of the heavy species 132 has not been accumulated,then the valve 44 is closed 126 and the tank 14 continues to accumulatethe layers 30, 32, 34 from the mixture by returning to step 112 ofintroducing 112 more of the mixture.

However, if the test 124 determines that sufficient quantity of theheavy species 132 has been accumulated, then the valve 44 may not beclosed 126 for long. Instead, the connector 102 a may be reconnected orredirected 128 to a different terminal disposition or tank. Then, thevalve 44 may open 120. Draining 130 may continue for the heavy species32 out of the tank 14. Again, after draining the heavy species 130 downto about the level of the top of the tank bottoms 34, a test 132determines whether the tank bottoms 34 have been sufficientlyapproached.

Also, the test 132 determines whether the tank bottoms 34 haveaccumulated excessively. If the tank bottoms 34 may be left where theyare, then again the process 110 returns to the step 126 closing 126 thevalve 44 and introduction 112 of the mixture continues.

Ultimately, there comes a point at which the light species 30 has beendrained 122, the heavy species 32 has been drained 130, and the test 132determines that the tank bottoms 34 need to be removed. At that point,closure 134 of the valve 44 permits a set up 136 of the valve 84.

Set up 136 may include connecting to the connector 102 b by other lines,and may include not only connecting 137 a but also back flushing 137 bthrough the valve 84 and annulus 100. Back flushing 137 b may beimportant to remove sediments that may have compacted and virtuallysolidified. Such compaction within the annulus 100, passage 98, orelsewhere in the leg 86 may completely stop outflow.

Following a back flush 137 b, reconnection 137 c may establish the openpathway from the tank 14. Sludge 34 must be freed from the tank 14 toflow through the annulus 100, and out the valve 84. Beyond theconnection 102 b sits some other containment or final disposition.

At this point, the opening 138 of the line 84 may not result in flow.Flow should result from or be accompanied by scrubbing 140 or otherwisedislodging 140 the tank bottoms 34. They cling to the walls of the tank14. Scrubbing 140 may cause or assist in fluidizing 142 the tank bottoms34. In some embodiments, additional liquid may have to be added. Forexample, scrubbing 140 may be done, or dislodging 140 may be done, by acomparatively smaller mass of hot steam.

However, fluidizing 142 may involve addition of water in order to betterfluidize or render the tank bottoms 34 of lower effective viscosity.More fluidity or cleaning may result from the presence (addition) ofother liquids such as solvents. Ultimately, the flushing 144 of the tankbottoms 34 results from the tank bottoms 34 having been fluidized 142,passing out through the annulus 100. The exit path includes the leg 86 bby way of the passage 98, to the valve 84, in its open 138 condition,and exiting through the connector 102 b toward a final dispositionlocation.

A test 148 determines whether the tank 14 will continue in service. Ifit is removed from service, then the cleaned tank 14 may be removed,with the valves 44, 84 closed. In fact, the entire fractionator 90 orany other portion of an adapter 16 may be removed, and the tank 14 maybe re-purposed. Otherwise, if the test 148 determines that the tank 14will continue in its current service, than the process 110 refers backto the introduction step 112 and continues.

The present invention may be embodied in other specific forms withoutdeparting from its purposes, functions, structures, or operationalcharacteristics. The described embodiments are to be considered in allrespects only as illustrative, and not restrictive. The scope of theinvention is, therefore, indicated by the appended claims, rather thanby the foregoing description. All changes which come within the meaningand range of equivalency of the claims are to be embraced within theirscope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. An apparatus operable as a separator comprising: a tankdefining a bottom, a wall, and a volume therewithin capable ofcontaining a mixture comprising fluids defining a liquid level andincluding at least two liquids, separable based on a first liquid beinglighter and a second liquid being heavier; a port penetrating the wallproximate the bottom between the volume and a destination outside thetank; a line as a conduit having first and second ends, being flexiblebetween the first and second ends thereof, and having a head, suspendedby flotation at the first end, capable of following changes in theliquid level by the flotation proximate the liquid level and being opento receive into the conduit a portion of the first liquid from proximatethe liquid level as the liquid level changes; and the line, wherein thesecond end is operably connected to pass content of the conduit outthrough the port.
 2. The apparatus of claim 1, wherein the mixturecomprises solid particles.
 3. Apparatus of claim 2, wherein the mixtureseparates over time the solid particles coated with a portion of thefluids, thereby rendering a sludge proximate the bottom.
 4. Theapparatus of claim 3, wherein the volume contains at least one gas abovethe liquid level.
 5. The apparatus of claim 1, the apparatus comprisesan adapter passing through the port, the adapter comprising a centraltube sealingly connected to drain the line through the second end andout through the port, and an annulus around the central tube and open tothe volume to be capable of draining the volume from proximate thebottom through the port.
 6. The apparatus of claim 5, wherein theapparatus relies on buoyancy differences between the first and secondliquids to separate them over time and direct them through the centraltube and the annulus, respectively.
 7. The apparatus of claim 1, whereinthe head operates as a snorkel head connected to feed the conduit with astream continuously flowing from proximate the liquid level as theliquid level drops in response to removal of a portion of the contentsof the tank through the port.
 8. The apparatus of claim 7, comprising abuoy operably connected to provide the flotation to the snorkel head toresist entrainment of a gas from above the liquid level into the streamby maintaining the snorkel head at an effective head depth below theliquid level.
 9. The apparatus of claim 8, comprising a plate, as anobstruction, operably connected to resist entrainment of the gas intothe stream by increasing a distance required for the first liquid at theliquid level to travel between a location in contact with the gas andthe first end.
 10. The apparatus of claim 1, wherein the apparatus isoperable on mixtures, containing a plurality of constituents, as one of:a liquid-liquid separator by installing through the port an adapterhaving a central channel connected to drain the first liquid from theline and an annulus surrounding the central channel to drain the secondliquid therethrough; a liquid-solid separator by installing the adapterand draining a sludge comprising solid particles in the second liquidand draining the sludge out through the annulus; a gas-liquid separatorby providing a vent in the tank to vent gases accumulating above theliquid line; and a combination of one or more thereof.
 11. A methodcomprising: selecting a tank having a port proximate a floor defining abottom thereof, the tank being capable of receiving, containing, andseparating, exclusively under the influence of gravity, a mixturecomprising at least two liquids defining a liquid level and separablebased on a first liquid being lighter and a second liquid being heavier;fitting to the port a valve assembly connecting to a snorkel extendingfrom a second end of the snorkel at the valve to a first end of thesnorkel, provided with an opening and provided with a structure capableof floating proximate a liquid level established by the mixture in thetank; adding the mixture to the tank; waiting a time selected for thefirst, lighter, material to separate from the second, heavier, materialin the mixture; and draining continually into the opening and outthrough the valve assembly a lightest portion of the lighter material.12. The method of claim 11 comprising closing the valve assembly inresponse to the liquid level dropping to a position corresponding to anunacceptable constitution of the liquid in the tank accessing theopening.
 13. The method of claim 11, comprising operating the snorkeland tank to separate the mixture, which also contains solids and gasthat accumulates above the mixture in the tank into at least one of: aliquid-solid separation of species separating solid particles as asludge below the second liquid after draining the first and secondliquids; a gas-liquid separation of species by venting gases from thetank above the liquid line; and a combination of two or more thereof.14. The method of claim 11, wherein the valve assembly comprises anannular passage surrounding a central passage, a first valve capable ofcontrolling streaming of a first flow from the snorkel through the portby way of the central passage, and a second valve capable of streaming asecond flow directly from the tank, proximate the bottom thereof, intothe annular passage through the port.
 15. The method of claim 14,comprising: operating the first valve to drain the tank of the firstliquid meeting a specification for purity; closing the first valve basedon when the snorkel begins draining the first liquid not meeting thespecification.
 16. The method of claim 15, comprising: operating thefirst valve to drain the tank of the first liquid not meeting thespecification; and closing the first valve in response to the second endof the snorkel approaching the second liquid below the first liquid. 17.The method of claim 16, comprising draining the second liquid from thetank by opening the first valve.
 18. The method of claim 17, comprisingdirecting the first liquid meeting the specification to a firstdestination, corresponding to a first disposition; directing the firstliquid not meeting the specification to a second destinationcorresponding to a second disposition; and directing the second liquidto a third destination corresponding to a third disposition.
 19. Themethod of claim 16, comprising draining a tank bottoms comprisingparticulate solids accumulated proximate the bottom of the tank byopening the second valve.
 20. A method of removing fluids from a tank,the method comprising: providing a snorkel connected inside a tank to aport exiting the tank proximate a bottom thereof, the snorkel isstructured for being capable of extending continuously from the port ata second end of the snorkel to a liquid level accessible continually bya first end thereof; adding a mixture to the tank comprising a mixtureof at least two liquids defining a liquid level, and separable based onthat a first liquid is lighter than a second liquid; waiting forseparation of constituents of the mixture into a vapor, the firstliquid, the second liquid, and tank bottoms containing solids asparticles; draining a purest portion of the first liquid continuallythrough the snorkel from proximate the liquid level so long as thepurest liquid comports with a specification for purity thereof; draininga non-compliant portion of the first liquid through the snorkel fromproximate the liquid level to proximate a top surface of the secondliquid below the first liquid; draining the second liquid through thesnorkel; and draining the tank bottoms through the snorkel.